Allowing unlicensed networks, i.e., networks that operate in unlicensed spectrum to effectively use the available spectrum may be an attractive approach to increase system capacity. While unlicensed spectrum can never match the qualities of the licensed regime, solutions that allow an efficient use of the unlicensed spectrum as a complement to licensed deployments may have the potential to bring great value to the 3GPP operators, and, ultimately, to the 3GPP industry as a whole. Such solutions may enable operators and vendors to leverage the existing or planned investments in LTE/NR hardware in the radio and core network.
Licensed-Assisted Access (LAA), which is an initiative for LTE to operate and support download (DL) traffic on unlicensed spectrum, was first introduced in LTE Rel-13. Enhanced LAA (eLAA) and Further enhanced LAA (feLAA) have been proposed to support both upload (UL) and DL traffic in unlicensed spectra in later releases. The LAA framework builds on the carrier aggregation solutions to access the additional bandwidth in the unlicensed band. Brief reference is now made to FIG. 5, which is a schematic diagram illustrating primary and secondary carriers operating in a further enhanced license assisted access network. As illustrated in FIG. 5, the primary cell (PCell) may retain the exchange of essential control messages and may also provide always-available robust spectrum for real-time or high-value traffic. The PCell also provides mobility handling and management for the user equipment (UE) via the high-quality licensed band radio access network with wide coverage. The aggregated secondary cells (SCells) in the unlicensed band, when available, can be utilized as bandwidth booster to serve, e.g., best effort traffic. The LAA SCell may operate in DL-only mode or operate with both UL and DL traffic.
Approaches described in the Background section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in the Background section are not prior art to the inventive embodiments disclosed in this application and are not admitted to be prior art by inclusion in the Background section. Therefore, any description contained in the Background section may be moved to the Detailed Description section.